Hand-operated grease gun



Jan. A31, 192s.

H. KREIDEL HAND OPERATED GREASE GUN Filed June 13. 1927 mm" www Wof Patented Jan. 31, 1928.

UNITED STATES HANS KREIDEL, 0F WIESBADEN, GERMANY.

HAND-OPERATED GREASE GUN.

Application led J'une 13, 1927, Serial No. 198,395, and in Germany `Tune 10, 1925.

All known hand actuated high pressure lubricating gunshave the defect that they are not sufficiently fluid tight when applying high pressures and when using consistent or liquid lubricants for example grease or oil, or when placed or held in different positions of operation. In order to overcome this objection, I construct the packings between the main piston and the lubricant container, the working cylinder and its guide piece, and between the plunger and the working cylinder in such a manner that the lubrieating gun operates eliicicntly in all positions and when using various kinds of lubricants even when applying the maximum pressure.

Instead of providing the main piston of the container with the usual cup leather lpacking it is rovided with a packing the marginal portion of which is adapted to spread. To the main piston is secured a disc of leather or the like of which the diameter is only slightly larger than the internal diameter of the supply container so as to form a marginal portion adapted to spread and whilst the main piston can be easily moved forwardly it can be moved in the opposite direction only with difliculty.

During the forward mov-ement of the piston,`

said flexible disc of leather or the like will engage the inner surface of the container along a single line formed `by one of the` edges of said marginal portion, the other edge of said portion being out of contact with the container. If however the weight or the resistance of the lubricant exerts pressure in such a direction as tend to arch or bend the marginal portion of said disc, both edges of said portion, and the entire peripheral surface of the disc, between said edges, in other words, a surface corresponding to the full thickness of the disc, will be pressed against the inner wall of thc. cylindrical container and thus presents a considerable resistance to movement of the main piston in the direction of the action of the Weight of the lubricant thus producing a very tight joint. The greater therefore the weight of the lubricant the higher will be the pressure acting upon the edge of the packing disc and thus more eliicient the packing and the greater will be the braking action applied to the main piston. A small chain secured to the main piston servesto enable the latter to be withdrawn from the container when this is to be refilled. In order that this may be readily effected I vplunger is outwardly packed by an elastic packing fitted into its guide piece and upon which there is constantly exerted the pressure of its return spring, whilst the packing of the plunger against the interior of the actual pressure ch-amber of the working cylinder is effected by a packing ring, of elastic materiahfor example leather or the like, clamped in its cylinder head, which packing ring projects freely inwardly and covers in the manner of a diaphragm an enlargement of the cylinder neck which is preferably in the form of a funnel andenlarged towards it. A portion of the lubricant enclosed in the pressure chamber of the working cylinder will endeavour to escape rearwardly when the lubricating gim is pressed upon the part to be lubricated or the lubricating nipple thereof and the plunger is thus forced into the pressure chamber of the working cylinder, Where the lubricant will be held back by the elastic packing ring and by a pressure acting thereon which is gradually increased, in accordance with the increase of the pressure in the Vpressure chamber of the 'working cylinder. By the compression of the packing ring the vertical wall of its circular aperture is thus pressed against a periphery of the plunger and surrounds this in a fluid tight manner so that no lubricant can return into the container and on the subsequent movement of the working cylinder on the plunger a. high and effective vacuum is produced in the pressure chamber thereof. As in the case of an increase of working pressure in the pressure chamber the annular wall of the elastic packing ring is always pressed more tightly against the lunger, the pressure on the packing whic forms the joint between the workin cylinder and its guide member, automatica y increases with the in- *reased tension of the return spring.

The accompanying drawing illustrates in longitudinal section one example of a construction according to the invention.

Figure 1 shows the high pressure lubricating gun in the inoperative position.

Figure 2 shows it in the operative position with the plunger in the lowest position, and

Figure 3 shows the main piston with the packing disc when being withdrawn from the supply container.

The lubricant container a is provided with a main piston Z) and a removable filling cover e, which latter is provided with a small air inlet hole. On the side of the main piston Zi facing the cover c there is secured, by means ot' an outwardly (lished rigid metal disc o. a second disc b2 of hard leather or other flexible material suitable for the purpose. This disc I): is only slightly larger than the internal diameter of the supply container so that its marginal portion will arch in the manner indicated in Figures l and 2 and will normallyv have a line contact along one edge with the inner wall of the container. When pressure is exerted by the liibricant in the container on the iiian piston b in the direction towards the cover c the marginal portion of the disc b2 spreads and bears firmly against the inner wall of the container with the full peripheral surface of said disc thus forming an effective joint. For the purpose of withdrawing they main piston trom the container I provide a small chain which, when the lubricating gun is ready for operation, is adapted to be accommodated in the space between the cover and the main piston. In order that this withdrawal may be readily effected the disc b2 is not secured to the main piston itself but to a spring bolt b3 guided in the main piston and having the chain attached thereto, said disc L2 being held between a collar on the spring bolt and the clamping plate o. Normally the flexible disc b2 is pressed upon the side of the main piston facing the cover c by the action of the spring bolt b3. By pulling the chain of the spring bolt and thereby coinpressing the spring ot' the latter the disc b2 is arched and separated from the piston at the center by reason of the resistance at the edge thereof. In this position it no longer opposes any considerable resistance to the withdrawal of the main piston (see Figure Il). I'Vhcnever the pull upon the chain of the spring bolt b3 ceases the spring will expand and again draw the disc b into its normal position on the face of the main piston.

In the reduced neck of the lubricant coritaiiier a is fitted a closing member d having a cap secured thereto which freelv projects into the container. v

To the cover of this closing cap is secured the plunger e. Lateral apertures f in the cap estabhsh communication between the container and the gun mechanism proper and permit the passage of the lubricant. A guide member g screwed into the closing member (Z serves to guide the working cyliiidci i which is adapted to .slide axially in relation to the plunger c. The rear part of the working cylinder forms the pressure chamber proper L. rIlie free end of the tnbular extension h of the working cylinder is provided with a nozzle i for application to the part to be lubricated. The top of the pressure chamber l1. is open towards the plunger e while at the bottom said chamber has an o'utlet aperture it which is closed by a iion-icturn valve 7i: mounted in the tubular extension ot' the working cylinder. 'l'he strengthened cylinder head /L4 which projects iiito the closing member (l limits the movement ol-the working cylinder in the guide member. A return spring Zis coiled around the working cylinder and at one end hears against the nozzle z' and at the other end against the guide member g. A protecting cap m is adapted to be litted over the front end of the lubricating gun when this is not in use and is adapted to be screwed on the external screw thread of the guide member g. For the purpose of proriding a tight joint between the working cylinder and its guide member there is provided in the latter, in accordance with the invention, an elastic packing n which is preferably always under the pressure of the return spring l, and for establishing a tight joint between the plunger e and the pressure chamber of the working cylinder a packing ring o of elastic material, for example leather, is clamped in the top of the pressuie chamber in such a manner that thc wall of its circular opening slides closely and tightly on the surface of the plunger when this passes therethrough during the operation of the gun.

Adjacent to the packing ring 0 which is lun held in position by means ot a metal ring no j?, over which the end of the working cylinder is spun. the pressure chambcr'lt is provided with a short enlarged portion 71 in which collects the lubricant which tends to escape rearwardly whilst thc working cylinder is being drawn over the plunger and exerts a high surface pressure upon the free annular edge ot the ring. which preslsure increases with the. working pressure. By reason ot' the resultant compression of the elastic ringl` which is firmly clamped on the outside, the passage therein is somewhat reduced and consequently the ring always bears tightly around the plunger.

For the operation of the high. pressure lubricating gun, this, as shown in Figure 2, after the removal of the protecting cap m, has its nozzle applied to the part to be lubricated and the container a is then pressed inwardly by hand. The return spring Z is thus tensioned and the pressure chamber h of the working cylinder It filled with lubricant moves along the plunger e, the non-return valve /c opens and allows the lubricant to escape, the'lubricant being applied to the part to be lubricated under pressure through the nozzle z'. As soon as the position shown in Figure 2 has been reached, the gun thus completely collapsed, the non-return valve 7c again closes. Whilst the return spring Z eX- pands and the plunger e is withdrawn from the pressure chamber it of the working cylinder a vacuum is produced by which, as soon as the packing ring 0 leaves the plunger e, fresh lubricant is drawn from the container a into the pressure chamber. The atmospheric pressure acting upon the main piston b in the container thus moves the main piston forwardly in the container a distance corresponding tothe quantity of lubricant which has been drawn into the pressure chamber. l

By reason of the means employed for obtaining a tight joint between the working cylinder and the guide member, as also between the pressure chamber of the working cylinder and the plunger, this action is also effectively maintained continuously even when using very consistent lubricants. When withdrawing the tightly clamped packing ring from the plunger the comparatively high vacuum produced in the pressure chamber is destroyed so suddenly that the lubricantis projected from the container into the pressure chamber in the manner of a recoil. It is pressed from thisv chamber by reason of the tight joint between the pressure chamber and the plunger, as also by reason of the impossibility of backward flow, therefore without any influence on the quantity, even under very high pressure, so that provision is made for a constant complete and uniform supply of lubricant to the part to be lubricated.

By reason of the particularvpacking of the main piston this piston is drawn up readily after each stroke of the gun whilst 'entirely excluding air and at the same time preventing the passage of lubricant to the nozzle which has been removed from the part to be lubricated or during the movement in the opposite direction, when the container is at the bottom, as the weight of the lubricant bearing thereon causes t-heedge of the flexible disc b2 to be pressed firmly and tight-l ly against the inner wall of the container.

Having thus described my invention what I claim as new and desire to secure by Letters Patent is l. In a lubricant gun, a lubricant container having a cylindrical inner wall, a piston slidable therein and provided with an aperture, a bolt mounted in said aperture, a rigid disc secured to said bolt, resilient means urging said'rigid disc toward said piston, and a flexible disc between said rigid disc and said piston, said flexible disc being of slightly greater diameter than the interior of said container and having its edge normally upturned and engaging said inner Wall.

2. In a lubricant gun, alubricant container having la cylindrical inner wall, a piston slidable therein, a flexible disc overlying said piston and normally contacting therewith, said flexible disc being of slightly greater diameter than the interior of said container and having its edge normally upturned and engaging said inner wall, a bolt reciprocably mounted in said piston and fixed to`said disc, and resilient means urging said bolt and said disc toward said piston.

3. In a lubricant gun, alubricant container having a cylindrical inner wall, a piston slidable therein, a flexible disc overlying said piston and normally contacting therewith, said iexible disc being of slightly greater diameter than the interior of said container and having its edge normally upturned and engaging said inner wall, a rigid disc overlying said flexible disc, a bolt reciprocably mounted in said pistonand ixedly secured to said discs, resilient means urging said bolt and said discs toward said piston, and means secured to saidy boltor moving the bolt and L the discs*I away from said piston.

' 4.' In a lubricant gun, a lubricant container having a cylindrical inner wall, a piston slidabletherein, -and a liexible disc connected,

with said'piston and overlying it, said. disc being of slightly greater diameter than the interior of said container and having its marginal portion normally upturned and in line contact only, alongone of its edges, with said inner, wall, said marginal portion being adapted, upon movement of the piston in one direction, to spread so as to establish surface contact of said portion with said inner wall on the entire peripheral Surface of the disc throughout the thickness of the disc.

In testimony whereof I atlixed, my signature.

HANS KREIDEL. 

